This invention relates to an oil feed system for an oil burner and, more particularly, to such a system in which a purge line is provided to recirculate standing cold oil through an oil preheater.
Such systems have been proposed previously but in general they have suffered from the drawback that they do not purge the standing oil right back from the nozzle and so a slug of unheated oil is injected into the nozzle shortly after start-up. Particularly in the case of used lubricating oil (waste oil) this unheated slug fails to ignite properly and can cause smoke and, possibly also, partial blocking of the nozzle after continued use.
In other systems where the purge line has been brought right up to the nozzle relatively complicated valve arrangements have been required and, in particular, structure for closing off the burner nozzle to the supply of oil has been incorporated.
It is an object of the present invention to provide an oil feed system for an oil burner which provides a cold purge phase in a simple and effective manner with an absence of expensive components.